Is it common for a mediator to force the plaintiff to defend documents that were never given prior to the conference?

Two days ago, in a settlement conference, the mediator told me that I had to agree to a sum he decided and I was never given any opportunity to see anything from the opposition. The mediator said that after looking at my medical records, the slip and fall, he could not see how I got the injuries I am claiming. I have two witnesses. I had some previous injury in my knee and neck area but the lumbar and thoracic area were affected. The mediator made me sign a document by intimidation, telling me I will not get a fair trial and that he feels the injuries sustained did not warrant continue pain for five years that it took to get to this point. The owner refused to cooperate and the attorneys both ignored the case for four of the five years. I was told specifically that I would not be testifying yet I was put under constant pressure by the mediator. I realized at home that the mediator had prior history with me, when he dropped a case because I asked him to remove a name from a lawsuit of an innocent person. He was angry. I think because he had my case file prior he was well aware of this. He also is a neighbor of the defendant who both live in an affluent small community. The defendant is a slumlord who refused to fix a dangerous area, that was the only way in or out. Is it common in a settlement conference to have each side separate? Is it common for a mediator to decide where the case numbers allowed start? Is it common for a mediator to make medical determinations as to the injury? Is it common that I be made to sign a document that states I have already been paid when the mediator refused to give me a check stating I have to pay back my insurance even though there is no lien and if I didn't accept that term, he will pay all of my award to the insurance and they can refund me? It is insurance I am already required to repay on death, from my estate.